Each stone varies. 
Green jade - Overall health and abundance. It directly effects the Heart Chakra (4th) and is most noted for its ability to allow one to truly enjoy their life. It also helps deter from the "scarcity" mindset involving money, fear-based decisions and greed. 
Physically, green jade is a tremendous heart healing stone and it aids in strengthening the nervous system.
Black jade - Protection, clearing negativity. This stone caters to all Chakras and helps one rid themselves of fear, envy, doubt, anger, hatred and other destructive and negative emotions. Black jade can also assist one in facing and integrating the shadow self.
Physically, black jade can protect against viral and bacterial infection, parasitic infestation and associated illnesses. It is an excellent tool to use when traveling.